From f2155d74d76ec1f731c500a32ea9f8a92f1aed1f Mon Sep 17 00:00:00 2001
From: mr314ot <mr314ot@sigma.tuke.sk>
Date: Mon, 17 Nov 2025 10:23:41 +0100
Subject: [PATCH] du6 - 11

---
 du6/program.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/du6/program.c b/du6/program.c
index cd8b9dc..7dbc15c 100644
--- a/du6/program.c
+++ b/du6/program.c
@@ -10,6 +10,8 @@ typedef struct tree {
     struct tree *right;
 } Tree;
 
+int valid_db = 1;
+
 //odstranit koncovy znak
 void strip_newline(char *s) {
     int len = strlen(s);
@@ -43,6 +45,7 @@ Tree* read_tree() {
     // inak nacitat oboch potomkov
     node->left = read_tree();
     if (!node->left) {
+	valid_db = 0;
         free(node);
         return NULL;
     }
@@ -50,6 +53,7 @@ Tree* read_tree() {
     node->right = read_tree();
     if (!node->right) {
         free(node->left);
+	valid_db = 0;
         free(node);
         return NULL;
     }
@@ -75,6 +79,8 @@ int count_leaves(Tree *t) {
 
 // spustenie znalostneho systemu
 void run_system(Tree *node) {
+    if (!node) return;
+
     printf("%s\n", node->value);
 
     // list -> koniec
@@ -106,7 +112,7 @@ int main() {
     Tree *root = read_tree();
 
     // nepodarilo sa nacitat koren -> chyba
-    if (!root) {
+    if (!root || !valid_db) {
         printf("Expert z bufetu to vie.\n");
 	printf("Chybna databaza\n");
         return 0;